1. Field of the Invention
This invention relates in general to the field of communications, and more particularly to a method and apparatus for reducing the latency associated with switching back to a high speed data network following a call over a circuit switched network.
2. Description of the Related Art
The cell phone industry is undergoing exponential growth, not only in this country, but all over the world. In fact, it is well known that the over twenty percent of the adult population in the United States do not even have a traditional landline telephone. In addition to those who do not own a conventional telephone, nearly ninety percent of the adult population owns a wireless phone.
And the usage of cell phones is increasing as well over the use of traditional landline telephone coverage. In fact, one in seven adults now uses only cell phones. Whereas in the past cell phones were used when a landline was not available or under emergency conditions, lower carrier rates, affordability of family packages, and free mobile-to-mobile or friend-to-friend promotions have fostered in significant increases in usage. It is not uncommon today to walk into any public forum or facility and notice a majority of the people there talking on their cell phones.
The ability to communicate using a mobile phone, or mobile station, has been available since the middle of the last century. However, during the 1990's so-called “2G” or second generation mobile phone systems were provided that began the growth in both deployment and usage that we currently enjoy today. These initial systems predominately provided for the routing and reliable servicing of voice calls between parties. And, as one skilled in the art will appreciate, there are a number of timing and latency requirements associated with transmission and reception of voice data in order to maintain quality of service. As such, so-called circuit switched voice links have been fielded that guarantee this quality of service.
And although wireless cellular network technologies have continued to provide improvements related to the ability to process voice calls, there has also been an enormous pull on the industry to provide for the reliable and efficient transfer of packetized data. As a result, the incremental developments in high speed data networks have not always tracked with the development of voice networks. It is a goal within the industry to field a more unified solution that would provide both reliable voice and high speed data access, however, the industry is not at that point presently. Consequently, it is common practice to field a mobile system that provides for voice communications over one type of network, say CDMA2000, and high speed data communications over another type of network, say LTE. In the near future, these hybrid solutions will be prevalent within the art.
In order to field such a hybrid system, designers are forced to develop protocols for those instances where two or more co-fielded networks create conflict. This application deals with one such instance, that is, the switching between a high speed data network that provides exclusively for packetized data communications and a circuit switched voice network.
Presently, protocols exist for fallback to a circuit switched network during a high speed data session in order to process an incoming or outgoing call. And provisions exist for a return to the high speed network, notably LTE, following termination of the call. However, the present inventor has noted that the provisions for return to the high speed data network introduce latencies in the system upwards to almost three minutes, which one skilled in the art would agree become significant performance and human factors issues. Although this maximum latency is not what an average user would experience, it is nonetheless probable and as a result is limiting.
Accordingly, what is needed is a technique that would eliminate or substantially reduce the latency experienced upon return to high speed communications following termination of a fallback circuit switched call.